The Double-Edged Alchemist
by Tom Felton Lover999
Summary: Rachel Mustang has never been in her brother's shadow, but now that Edward and Alphonse are uncovering dark secrets. Roy decides she needs to be more under his control. Will Rachel be able to help the Elric brothers? Or will her brother send her away before she has a chance? And what will Roy do when she moves up in rank out of the blue? Follows Fullmetal Alchemist: Brotherhood.
1. Chapter 1

Roy Mustang stepped out and into an empty hallway or he thought it was empty. A tall woman was hiding within the shadows. Her slick black hair was back in a braid that was reached the middle of her back. Her gold eyes shot up and she straightened out her blue military uniform. She had white gloves on one hand that looked exactly like his while the other had a completely different symbol on it. "How much did you hear?"

She pushed herself wall and uncrossed her arms. "Just that his name is Isaac McDougal. Formally known as the Freezing Alchemist. Blah blah blah. He brought up the Elric brothers, and then some idiots ran by so I couldn't hear anymore." Colonel Mustang chuckled and glanced down at his only blood relative that was still alive.

Rachel Mustang. His younger sister who was just three when their parents died, both of them practice flame alchemy but her left hand was different, she could snap her fingers and produce rocks like nothing. Once she learned flame alchemy she went off on her own to learn even more. As much as Roy hated to admit it, his sister knew a lot more about alchemy than he ever would. "Find the Elric brothers and help them bring him down."

She stopped and looked up at two windows. She chuckled and sprinted up a pillar. She jumped through the window and onto the roof. "Rachel!" Roy yelled. "You know you'll never be able to control her, Colonel." Roy looked over his shoulder at Lieutenant Hawkeye.

"I'm well aware, Lieutenant. I just wish she wouldn't destroy property!" He yelled. Rachel brushed off the glass off her uniform and glanced to her left. Edward was clutching onto Alphonse with wide eyes. "I hate how you appear out of thin air, Rach!"

"This was the quickest way to the roof. You two are so easy to track. Now let's go capture this asshole and be done with it." Rachel mumbled. Ed chuckled and took off running. Alphonse and Rachel quickly followed him. It wasn't hard to find him. Steam and ice was what lead them to the Freezing Alchemist. "He's down this alleyway." Alphonse muttered.

Rachel dashed off before Ed and Al could even question her. Ed knew she was incredibly smart so he wasn't worry about her at all. Ed slammed his hands into the wall creating pillars to shoot out towards the Freezing Alchemist. He easily dodged them and stopped.

"A man in armor. You must be the Fullmetal Alchemist!" He growled. "That's me!" Ed screamed glaring over at the man. "You?! You're nothing but a tiny child!"

Ed's face dropped and his clapped his hands together causing stone to go flying towards his head. "How is that for small?" Ed yelled. The Freezing Alchemist let out a low chuckle shaking his head. Ed gritted his teeth together and smirked when he saw the raven headed beauty drop down from a nearby roof. The Freezing Alchemist quickly turned around just in time as a ball of fire shot his way. In a blink of an eye; the flames turned into steam and he laughed loudly.

"I finally get to meet you. You're the Flame Alchemist's sister! The Double-Edged Alchemist."

Rachel lifted up her left hand and snapped her fingers. A large rock hand appeared from the ground and wrapped quickly around the Freezing Alchemist. He struggled against the closed hand and glared at the 22 year old Alchemist. "Your title fits you well."

"I can't be living in my brother's shadow now can I?" She hissed. Soldiers suddenly appeared and Rachel dropped the hand slowly so the men could tie him up. "That was too easy." She muttered as she walked away with the Elric brothers. "You were awesome, Rach!" Ed yelled clapping his hand on her back. She shrugged and heard a commotion behind them.

The soldiers were lying on the ground burnt. "Damn it!" Ed screamed. Rachel hissed, "Find him. I'm going to send Major Armstrong to help you. Figure out what his mission is. I'm going to go speak with my brother." Ed and Al nodded sprinted off.

Rachel took off out of the alley way and sprinted towards the direction of the soldiers. One of the men pointed out where her brother was and she was off. "Riza!" Riza Hawkeye turned around; her face was cold of emotion like it always was. "Where is Roy?"

She nodded her head to the front of the pack of soldiers. He was yelling at the Freezing Alchemist who was standing on the edge of the roof. He was surrounded but his cocky personality didn't fade at all. He seemed more pumped than he was when she captured him. Rachel glanced down at the box in Hawkeye's arms. "Oh, well I supposed he was already well prepared." She muttered.

An ice wall appeared and before Rachel could stop her brother, he unleashed his fury. His fire turned the ice wall into water and Roy growled. He pulled off his wet glove and snatched a new one from the box. "At least you still have another glove that will protect you. He is useless when he gets wet." She muttered walking after the Colonel.

"Rachel!" She ran to her brother's side and could feel the utter rage bubbling through his skin. "You had him and then lost him."

"Well to my defense, the soldiers lost him." She could feel her brother's glare but decided to ignore it. She hated that he out ranked her so therefore she had to listen to him. "What is his plan?" Rachel asked as she tightened her gloves around her wrist.

She watched as ice slowly took over Central and gasped, "He's going to destroy Central."

"He has transmutation circles everywhere. Destroy them and we will handle McDougal!" Ed and Al chased after McDougal and Rachel stared at her brother for instructions. Major Armstrong appeared and Rachel groaned when he appeared without a shirt on again. When any situation got difficult, Armstrong always took his shirt off.

"Go!" I took off towards the south side of the city while Armstrong took the other side. Rachel noticed a bunch of ice around an alley way. She snapped her fingers together and a burst of fire shot towards the ice easily melting it. She snapped her fingers yet again and causing the ground to crack in half. "One down!" She hissed. She took off running and easily found another one. She destroyed it just like the first one and took off running again. She heard talking in the distance and picked up her sped. Maybe she would be able to capture him again.

She peeked around the corner and saw the Fuhrer standing over the body of the Freezing Alchemist. She dashed down the alley way and her eyes widen at the bloody scene in front of her. "Good job, Double-Edged"

"Sir?" She whispered. Her eyes were glued to the dead corpse. She knew the Fuhrer was powerful when it came to his sword but she had no idea he was this gifted. He didn't have a drop of sweat on his forehead and he didn't look phased at all. He was about to open his mouth when Ed, Al, and Major Armstrong appeared. "Good job all."

And with that he walked away like nothing happened. "What happened?" Ed asked. Rachel lightly shook her head, "No idea. I didn't see it." He patted her on the back and walked away with Alphonse following him.

That's when Rachel realized something was not right and she had an idea Ed knew what that strange feeling was. And she was going to get that out of him.


	2. Chapter 2

"You two have a safe journey, okay?" Rachel shook Ed's hand and he leaned back in the window. They were on the way to Liore to see a priest. "We just hope he has a philosopher's stone." Alphonse said cheerfully. Rachel smiled and looked over at Ed; he was staring off with this look of determination on his face. "From the reports, that's what it sounded like." The train blew its horn and Rachel stepped back waving at the boys. Alphonse leaned out the window, "See you later, Rachel!"

Rachel stepped back and smiled as she watched the train disappeared. It seemed just like yesterday; Edward came to Central to get his state alchemy license.

"_**This is ridiculous, Roy! He's just a child. You can't expect him to pass. He's twelve. I'm nineteen and just got mine five months ago. I had a hard time passing." Rachel hissed as they made their way to watch Edward Elric. "You didn't see his eyes like I did. He had fire in his eyes plus he performed human transmutation. He's gifted." Roy hissed the last part. Rachel stopped short and pulled him to a stop. **_

"_**The Fuhrer doesn't know that, does he? You know how big of a taboo that is." Roy quickly shook his head and tugged on his sister's arm. "Only you and Lieutenant know." Rachel shook head as Roy pushed open the doors. They took their seat and Rachel watched as a young blonde headed boy walked in. He had a smug look on his face and glanced over at Roy. **_

_**The Fuhrer walked into the room and Rachel couldn't get over by how small Edward looked compared to the guards that surrounded him. "Do you need chalk to draw a transmutation circle?" Edward waved off the guard and clapped his hands together. **_

_**A sword slowly appeared out of the ground and she heard her brother gasp, "He didn't even use a transmutation circle!" In a blink of an eye, Edward sprinted off towards the Fuhrer. He placed the sword in the Fuhrer's face but froze. "A lot of people would take this as the perfect chance to kill you." **_

_**The Fuhrer laughed, "You have guts. I like that." He stepped back from Ed and the tip of Edward's sword fell to the ground. "When did he draw his sword?" Ed whispered. **_

"_**I mean the kid has a point" She whispered as they left the room. Roy shot his sister a look but she shrugged and walked ahead of him. She already knew that Edward Elric was officially the youngest State Alchemist. **_

"Are they on the train?" Roy asked without looking up. Rachel plopped down on the couch and leaned back. "Yep, Alphonse was excited and Edward had that normal fire that you are always going on about." Roy looked up and smirked. "You don't think it's a philosopher's stone, do you?" Roy folded his hands under his chin and had a sly smile on his face.

"I think it's a fake. But I could be wrong." Rachel said picking at the black nail polish that was chipping away on each finger. Roy didn't say anything, he just went back to staring at his paperwork. A few moments of silence went by before his office door opened again, Maes Hughes appeared with his normal goofy smile on his face.

"Congratulation to both of you for bringing down the Freezing Alchemist!" Maes tossed me the folder and I frowned. "No, that was all the Fuhrer." Roy said.

"Not according to the Fuhrer. He says it was all you, Rachel, and the Elric brothers." Maes said leaning against the oak desk that Roy was sitting behind. Rachel through the report and saw that Maes wasn't lying. The Fuhrer was actually giving them all the credit but why?

She froze when she saw a word she has never seen before. She quickly stood up and walked over to the pair. "What's alkahestry?" Roy took the paperwork from her and looked over the word. He showed it to Maes who also looked just as puzzled as Rachel and her brother. "No idea. Why?"

"It says that's what he was using. It would make sense. He was difficult to bring down." Rachel said as she picked up the paperwork again. Before she could look at it again, Maes snatched it out of her hands.

"Word of advice to both of you: when a person in higher command gives you the credit. You accept it. Have a good day Colonel and Major." Rachel gave him a tight nod while Roy stared off into the distance. Rachel stretched and was about to say her goodbyes when Roy turned his attention to her. His eyes were dull but she could see a hint of worry in them. "I'll be heading back to Easter Command soon, so you won't have your older brother here to protect you anymore." He said jokily. But Rachel knew this conversation was about to turn serious.

"I'll be gone awhile until I get transferred back to Central. I am leaving Major Armstrong in charge of you." Rachel whipped around so fast that she almost lost her balance in the process. She knew her brother was always protective over her but to tell someone to watch after her was insane. She was a grown woman and it was time for him to realize this.

"I have been in Central since I became a State Alchemist! Has Armstrong been watching me all this time!" She was having a hard time controlling her anger towards her brother but she was just blown away by how he was acting. "Something is going on, Rach. And you know I'm right. You are a skilled alchemist but I am your older brother."

"I am known as the Double-Edged Alchemist. I'm the second youngest Alchemist known plus you never see a female State Alchemist. You are being stupid and you know it." She plopped down on the couch so she could stop herself from slapping her brother.

"You know you are having the same feeling as I am. You just need someone on your side that has muscles. Major Armstrong is that man." He was right and she hated it. She stood up and sighed, "Fine. I'm going to go get some food"

He nodded and went back to his paperwork. Rachel quickly left as Riza was walking in. Riza saw the look on Rachel's face and sighed. "I tried to talk him out of it. He just wants to make sure you are safe while he isn't her. Don't hold that against him." Rachel nodded and quickly walked down the hallway.

"_**Hmm, Double-Edged Alchemist. I like it!" Rachel said spinning around. She placed her silver pocket watch in her pocket and looked up at Maes. "You know your brother is going to be furious" **_

"_**That's exactly why I didn't tell him. I guess I'll head over to-" Rachel froze as the door slammed open and Roy came storming into the office. "You are an evil little man, aren't you?" She hissed glaring at Maes. He grinned and shrugged. **_

"_**HOW DARE YOU?" Rachel flinched as his tone and went ahead to sit down. She looked over at Riza, who just mouthed sorry and stood still behind Roy. "You are in the military! Why can't I be? I'm just as skilled as you are." **_

"_**I haven't seen you in two years and then I hear that my sister just became an State Alchemist! My own sister didn't even ask me if it was alright" Roy just kept screaming and Riza flinched when his last sentence left his mouth. Rachel was not the type of woman that took orders from men. **_

"_**Excuse me?" She hissed. Roy quit his rant and froze. He stared at his sister. Her eyes were deadly. He could tell that she was furious. And that's when Maes realized that the only thing Roy Mustang was afraid of was his very own sister. "This is a dangerous job, Rach." Roy lowered his voice and stepped closer to his only blood relative that was still alive. **_

"_**You don't think I know that. I trained with you remember? Just let me live my own life, brother." Roy just growled and nodded. She was nineteen after all. She was a woman now. **_

"Major Mustang!" Rachel looked up from her untouched food to see Major Armstrong walking towards her. "Oh shit." She muttered, he had a grin across his face and she just knew she was about to receive one of his bone crushing hugs. Before she could even blink, she was being crush in Armstrong's arms.

"You must be so upset that your brother is leaving! I AM TERRIBLY SORRY! I AM HERE FOR A SHOULDER TO CRY ON!"

She gasped, "OKAY! PUT ME DOWN, MAJOR!" She could feel her oxygen cut off. He dropped her down roughly and Rachel took in as much oxygen as she could into her lungs. She sat back down and he sat down across from her. He leaned forward, "Did you see the paperwork?"

"Yes I did."

"Do you know what it means?" He asked in a hushed whispered. "I don't know but I am sure that Fullmetal will figure it out. He and his brother knew something that we didn't. Something doesn't feel right, so keep your eyes and ears open. Let me know if you hear anything." He tightly nodded and stood up. Rachel watched him leave and sighed.

_At least he is still a good man. _She thought as she gather up her tray of food.


	3. Chapter 3

Rachel had been reading none stop. She was trying to figure out what the Freezing Alchemist was using. So far, she was turning up empty. She even paid Armstrong to do some research and nothing. She slammed the book close and stood up. She placed it back on the shelf and heavily sighed. "Major Mustang?" She looked up and saw Jean Havoc. He had to be the most attractive man, she has ever seen. She could see his muscles ripping through his uniform and his blonde hair was messy. She was still surprised that her brother hadn't left for Eastern Command yet. He was driving her insane.

"Did my brother send you to follow me around like yesterday, Havoc?" She asked, she smirked and placed a hand on her hip. Jean smirked and leaned against a bookcase. He would be a fool not to flirt with her. Rachel was beyond gorgeous, the only reason he hasn't taken her on a date was because she was his commanding officer's little sister. He suddenly remembered why he was there in the first place and straightened up. "Actually, Hughes wants you in his office ASAP." Rachel nodded and walked around him quickly.

Jean turned around and watched her leave. He couldn't help himself stare as her hips swung as she walked. Rachel quickly made her way to Hughes office and walked in, she froze when she saw Fuhrer King Bradley standing there with Hughes and Major Armstrong. "Ah, Major Mustang!"

Rachel stood up straight with her arms folded behind her back. "I supposed you heard about the recent State Alchemist's deaths." Rachel slowly nodded and stood beside Major Armstrong. "I want you three to bring down the man who is behind this. No matter what. Understood?"

"Yes sir!" All three of them chimed. He nodded and quickly left Hughes' office. The second the door slammed shut, Rachel released the breath she didn't know she was holding and turned towards the pair. "So, what do we know about this murderer?"

Hughes flipped open a folder and frown. "Not much, but he has an 'X' shape scar on his face. That's all that is known." I gently took it from him and stared at it for a long time before handing it back to Hughes. "So, you two watch yourselves. He is targeting only State Alchemists."

"When are Edward and Alphonse coming back?" Rachel asked quickly. She knew that Edward would be targeted as well. Edward was just a child. He may think he could handle himself but this man is killing the top State Alchemist so easily. Maes looked down at his watch and grinned. "In an hour. Would you like to meet with them, Rachel?"

Rachel handed back the file and nodded tightly. At least she knew her brother could talk some sense into the pair. Rachel quickly left Maes' office and took a deep breath when she stepped out into the hallway. She didn't realize how worry she was about the boys. She calmed down and made her way to the station.

000

"Welcome back!" Rachel called out. Alphonse grinned and raced towards Rachel. He wrapped her up in his metal arms and picked her up hugging her tightly. She winced and rubbed her shoulder as he slowly released her. "Ah Rach! I'm glad they sent you and not your butt ugly brother" Edward said laughing. He patted her roughly on the back and they began walking back towards her car. She kept alert. She couldn't help but feel like she was being watched.

_I'm just being paranoid. _

"How was the mission?" Rachel asked as she started the car. Ed sighed loudly and stared out the window, "The stone was a fake. But we brought the bastard down so I guess in the way it was a success." Rachel tensed up and mumbled an apology. She knew they had no idea what she was the one that gave her brother all the information about the priest and hinted out letting them go. Alphonse seemed perfectly fine with it but Rachel could tell that Edward was troubled by it. She knew he would take it harder than Alphonse. Ed felt guilty and he thought he was about to find the one thing that would bring his brother back.

The rest of the ride was completely silently and both brothers just simply followed her into Central Command. She strolled straight to her brother. She knew he would be able to offer them more than she ever could. She pushed open the door to her brother's temporary office and saw him sitting behind his desk doing some work.

"Here are the Elric brothers." She monotone, she was still irritated with him that he was making her feel like she was completely helpless. He just motioned them in and she followed. She plopped down on the couch and kicked her feet up leaning back. Edward began to explain to him what had happened and Roy sighed. "Well, I do have someone else you can get some information from. His name is Shou Tucker"

"He's known as the Sewing-Life Alchemist. He has an extensive research library; there might be something in there about the philosopher's stone." Rachel spoke up, she was amazed that Roy was giving them this information. Then she realized why he was telling him this information… He didn't want to be in debt to Edward. She huffed and stood up angrily. That's how her brother was. He always thinking of himself, she felt his eyes on her and heard him also huff. "Why don't you two head out to my car? I'll meet you there to take you to Mr. Tucker." Ed just nodded and stood up with Alphonse quickly following him.

"Why are you mad at me now?" He asked folding his hands under his chin. "Why can't you just do something for them because you want to help? You just don't want to be in debt to Edward." She hissed staring at him. He chuckled and shook his head. "It's more than that. I cannot explain it to you, Rachel. Meet with Havoc in the library. You two can do some research and then pick up the brats." He stood up quickly and left the room. She chuckled and stared down at his desk.

"Roy, you are too kind." She reached across his desk and brushed some of his paperwork to the side. There was a folder with her name written on it with the words, 'please read' underneath it. She snatched it up and made her way to the library. She knew there was a reason she wanted her to be in a room alone with Jean Havoc… And it was in this folder.


End file.
